Insulation barrier and a method of making an insulation barrier

ABSTRACT

The insulation barrier is formed of a body of foamed polystyrene, either expanded or extruded, which is provided with a protective coating formed of a metallic-based inorganic material and is applied over at least one surface of the body. Optionally, a fire resistant composition of any inorganic silicate, boric acid, any salts of boric acid, hydrated sodium borate (borax) or mixtures thereof, and preferably sodium silicate, is applied in solution form and maintained within the body by a wetting agent in the solution. The protective coating is being applied by a coating roller followed drying of the polystyrene body.

This is a divisional of application Ser. No. 08/493,771, filed on Jun.22, 1995, now U.S. Pat. No. 5,590,501.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an insulation barrier. More particularly, thisinvention relates to a method of making an insulation barrier for a roofinsulation system as well as a ceiling system.

2. Description of the Prior Art

As is known, various types of insulation systems have been employed inbuilding construction. For example, insulation systems have been knownto use insulation materials in rigid and blanket form, for example madeof wood, glass, urethane, polystyrene and the like.

In the case of roof insulations, it has been known that built-up roofsof asphalt have not been able to produce all the characteristics of anoptimum roof. That is to say, built-up roof of asphalt is flammable,relatively heavy and of low insulation value. In order to improve theinsulation qualities of a roof construction, use has been made ofurethanes since such types of products provide a better insulation andare of relatively light weight. In addition, urethanes permit thermaldrift and require ozone depleting blowing agents. Hence, urethanes tendto be of higher costs and are not as environmentally friendly as onewould desire. In addition, urethanes being of open cell constructiontend to absorb water.

It has also been known that expanded polystyrene can be used as aninsulation material particularly since expanded styrene can bemanufactured at relatively low cost, is stable, is easy to install andabsorbs less water than urethane. However, expanded polystyrene does nothave a flame-spread capability to permit use on roof deck assembliesthat have metal decks. Instead, expanded polystyrene insulation must beseparated from the metal deck by means of an approved thermal barrier,such as sheet rock, perlite, polyisocyanuate (PIR) or polyurethane(PUR). For example, guidelines that usually determine products that canbe approved for roofing applications are set by local building codes.Some building codes follow the Uniform Building code which requires thata roof deck assembly with a metal deck substrate using expandedpolystyrene (EPS) as an insulation board, must have a thermal barrier of3/4 Perlite or 5/8 inch gypsum wall board installed between the metaldeck and the EPS. Instead of using such wall board, any proposed roofassembly must successfully perform an insulated steel deck test. In thisregard, there are two recognized agencies that perform an insulatedsteel deck test, one is Factory Mutual under F.M. test number 4450 andthe other, Underwriters Laboratory under U.L. test number 1256.

Still further, it has been known to provide various types of substrateswith coatings or the like in order to increase the flame and heatresistant characteristics of the substrate. For example, U.S. Pat. No.4,647,500 describes a foamed plastic composition in which a coating ofan inorganic binder composition is placed on the surface of the foamedplastic with or without the interposition of an elastomer coating. Asdescribed, the inorganic binder composition is liquid and comprisescolloidal silica, monoaluminum phosphate and aluminum chlorohydrate. Asan option, an alkyl tin halide catalyst may be employed to improve thebonding between the binder composition and the surface to which thecomposition is applied.

U.S. Pat. No. 4,702,861 describes a flame retardant coating which can beapplied to various types of surfaces including synthetic resin foams inorder to create a substantially continuous protective film so as toencapsulate and surface-envelope the structure onto which thecomposition is applied. As described, the coating is made from a workingaqueous latex dispersion. In addition, the composition may be mixed withsodium silicate.

U.S. Pat. No. 5,035,951 describes a composition for retarding flamewhich employs a water soluble alkali metal silicate such as sodiumsilicate.

Similar coatings for flame retardation which employ sodium silicate, atleast in part, are also described in U.S. Pat. Nos. 2,407,615;4,179,535; 4,710,309; and 4,888,057.

Other materials have also been known for use in fire retardingcomposition such as hydrated aluminum silicate, as described in U.S.Pat. No. 3,490,065; aluminum hydroxide, as described in U.S. Pat. No.5,034,056 and hydrated alumina or magnesium hydroxide as described inU.S. Pat. No. 5,215,581.

Still further, it has been known to provide a polyurethane foam with acoating of an intumescent material, for example, vermiculite coated withammonium phosphate, such as described in U.S. Pat. No. 3,455,850.

Despite the knowledge of using coatings of various types on substratesas well as compositions in a substrate to enhance fire retardantcharacteristics, there has been no product on the market which employs afoamed polystyrene as a flame retardant insulation barrier particularlyfor metal roof decks.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an insulationbarrier made of a foamed polystyrene which can be used on a metal roofdeck without the need for a thermal barrier.

It is another object of the invention to provide a foamed polystyreneinsulation barrier which has an enhanced flame and fire-resistantcharacteristic.

It is another object of the invention to improve the fire-resistantcharacteristics of foamed polystyrene insulation.

It is another object of the invention to reduce the cost of constructinginsulated metal roofs.

Briefly, the invention provides an emulsion barrier which is comprisedof a body of foamed polystyrene, either expanded or extruded, having aprotective coating including a metallic-based inorganic material, forexample, aluminum oxide trihydrate, hydrated boron oxide, antimonyoxide, titanium dioxide, and/or magnesium hydroxide, on at least onesurface. The protective coating may also include an organic emulsion,for example, latex. Optionally, the body may be impregnated with a fireresistant composition, such as any inorganic silicate, boric acid, saltsof boric acid, hydrated sodium borate (borax) or mixtures thereof.

The invention further provides a method of making an insulation barrierincluding the steps of obtaining a body of foamed polystyrene, forexample in continuous form or in panel form. An emulsion of a metallicbased inorganic material, such as hydrated alumina, and a latex, is thenapplied to at least one surface of the body followed by drying of theemulsion in order to form a protective coating on the body.

Optionally, the method may also include the step of forming a pluralityof recesses in at least one surface of the body and impregnating a fireresistant composition, preferably of sodium silicate and a wetting agentinto the recesses. Impregnation may occur by spraying, flood coating,roll coating or manually applying the solution onto the top surface ofthe body of foamed polystyrene so that the solution passes into therecesses and permeates into the interior of the polystyrene.Alternatively, the protective coating may be applied prior to drying ofthe impregnated polystyrene body, for example, to provide a one-stepapplication of the impregnant and the protective coating.

The impregnation of the foamed polystyrene body with the fire resistantcomposition of, for example, sodium silicate serves to enhance thefire-resistant and strength characteristics of the foamed polystyrenewithout compromising the insulation qualities of the polystyrene.

Once the fire resistant composition penetrates the foamed polystyrenebody a layering effect is believed to begin to take place in the fireresistant composition, particularly, sodium silicate, within thepolystyrene. The application of the emulsion of the hydrated alumina isbelieved to accelerate the multiplication of the silica layers whichoccurs within the polystyrene body while coating one side of the body.During the subsequent drying process, aging takes place during which alarge increase in strength characteristics takes place within the closedcell polystyrene body. This is believed to take place chemically by apolymerization process between, for example, the sodium silicate andhydrated alumina.

The resultant insulation barrier has been found to possess outstandingfire performance characteristics that will pass the UnderwritersLaboratory test number 1256 for interior fire exposure without he use ofa thermal barrier.

In comparison with other known products, the resulting insulationbarrier of foamed polystyrene is most stable in the area of aged thermalvalues and product stability. Further, the insulation barrier can beplaced directly on top of a steel roof deck because the insulationbarrier contains within itself the ability to withstand server fire.

The insulation barrier possess several advantages. First, because thebarrier does not use chloroflourocarbons (CFC's) orhydrochloroflourcarbons (HCFC's) the barrier is less harmful to theenvironment than materials using such compounds. Further, the insulationbarrier has excellent fire-resistant characteristics and under actualfire situations has been found to release a reduced amount of toxicgases.

The cost of producing the foamed polystyrene insulation barrier isrelatively low. further, the labor required for incorporating thebarrier into a roof insulation system is relatively low. In thisrespect, the barrier is light weight, easy to handle and easy toinstall.

The insulation barrier has a stable thermal performance capable ofmaintaining a high R value of the anticipated life of the insulationsystem in which the barrier is employed. Also, waste of important energyproducts passing through a roof because of unrealistic thermalperformance ratings is reduced.

These and other objects and advantages of the invention will become moreapparent from the following detailed description taken in conjunctionwith the accompanying drawings wherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of a polystyrene insulationbarrier of panel shape constructed in accordance with the invention;

FIG. 2 schematically illustrates an apparatus for producing aninsulation barrier in accordance with the invention.

FIG. 3 illustrates a view of the insulation barrier employed in a roofinsulation system;

FIG. 4 illustrates a cross sectional view of modified roof insulationsystem employing an insulation barrier in accordance with the invention;

FIG. 5 illustrates a cross sectional view of a further roof insulationsystem employing an insulation barrier in accordance with the inventionin a tapered arrangement; and

FIG. 6 schematically illustrates a nanostructure which is believed tooccur within the foamed polystyrene body in accordance with theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the insulation barrier 10 is constructed in panelform, for example in panels having a length of 96 inches, a width of 48inches, and a thickness in the range of from 1/2 inch to 10 inches.Typically, the panels would have a 2 inch thickness.

The insulation barrier 10 is formed of a body 11 of polystyrene, eitherexpanded (EPS) or extruded, having closed cells. In this respect, thepolystyrene may be foamed in any known suitable manner.

Typically, the foamed polystyrene body 11 is obtained with a flat bottomsurface and a flat top surface which may be parallel or tapered relativeto the bottom surface.

The insulation barrier 10 also has a protective coating layer 12 on thesurface which is to be disposed in facing relation to the space in whicha flame may be generated. When the insulation barrier 10 is to beinstalled on metal deck, the protective coating would be placed on atleast the bottom surface of the body 11 which bottom surface would be infacing relation to the metal deck. Alternatively, the protective coating12 may face in the opposite direction, depending on the application.This protective coating 12 is formed of a metallic-based inorganicmaterial, such as aluminum oxide trihydrate, hydrated boron oxide,antimony oxide, titanium dioxide, magnesium hydroxide, and mixtures oftwo or more of such compounds. Optionally, the barrier 10 may also havea fire resistant composition, preferably selected from any inorganicsilicate, such as sodium or potassium silicate, boric acid, salts ofboric acid, hydrated sodium borate (borax) and mixtures thereof.

Referring to FIG. 2, in order to make the insulation barrier 10, thebody 11 of foamed polystyrene which is obtained in continuous sheetform, or in panel form, may be fed by a suitable conveying means along apredetermined path into an optional penetrating station 13 having apenetrating means in the form of a pair of rollers 14, 15 as indicated,the upper roller 14 is provided with a plurality of projections 16 whichare randomly or uniformly spaced circumferentially and transversely onthe roller 14 while the bottom roller 15 is smooth-surfaced.Alternatively, both rollers 14, 15 may have projections thereon. The tworollers 14, 15 serve to provide a nip therebetween which is equal to orslightly less than the thickness of the body 11 of expanded polystyrene.As the foamed polystyrene body 1 passes between the rollers 14, 15, theprojections 16 on the upper roller 14 punch through the skin normallyfound on the body 11 to form recesses 17 in the upper surface of thepolystyrene body 11. For example, where the polystyrene body 11 is of athickness of 2 inches, the recesses 17 may penetrate 1/4 inch into thetop surface of the body 11, being spaced apart on one inch centers.Typically, the projections 16 on the roller 14 are of 1/8 inch to 3/8inch diameter so that the recesses have a diameter of 1/16 inch to 3/8inch and penetrate to a depth of form 1/16 to 7/8 inches.

The optional penetrating station 13 may employ any other suitable meanswhereby recesses, cuts, indentations or the like are formed in the skinat the top surface and/or the bottom surface in the traveling body 11 offoamed polystyrene in order to permit penetration of fire-proofingmaterial. For example, knives or saw cuts may also be used for thispurpose.

Thereafter, the traveling body 11 may be passed through an impregnatingstation 18, which also is optional, wherein a solution including a fireresistant composition, as previously described, is applied to the topsurface of the body, for example by spraying from a suitable sprayer 19.

The preferred solution which is applied to the traveling body 11 atstation 18 is made of sodium silicate, water and a wetting agent. Thewetting agent may be Pentex No. 99 (a vinyl acetate/ethylene and vinylchloride polymer made by Rhone Poulenc) or Tween 20 (a polysorbate 20sold by ICI). for example, the solution may be made in weight % asfollows:

Sodium Silicate--65 to 85%

Water--14.2 to 34.2%

Wetting Agent--0.01 top 0.1%

Preferably, the solution is made of 78% sodium silicate, 21.7% water and0.03% wetting agent. The solution is applied at a rate of from 1 to 6pounds (wet) and preferably, from 2.5 to 3.0 pounds (wet) per sheetwherein the sheet has a typical width of 48 inches, a length of 96inches and a thickness of 2 inches.

Alternatively, the solution may be applied to the bottom of thetraveling body 11 or to both the top and bottom of the body 11 viasuitable means such as a machine employing coating rollers for coatingthe top and bottom surfaces of a traveling body.

Thereafter, if the body is passed through station 18, it is nextdirected through a pair of guide rollers 20 of the conveying means, anddelivered into a drying station 21, for example in the form of a heattunnel. The impregnated body 11 is then dried, for example at atemperature of from 140° F. to 200° F. for a time period of 6 to 12minutes.

Thereafter, the body 11 is conveyed to a coating station 22 in which aprotective coating is applied to the top surface of the body 11. Ifoptional penetrating station 13 and impregnating station 18 are omitted,the body 11 of foamed polystyrene may be fed directly by the conveyingto coating station 22. As indicated, the protective coating can besupplied from a spigot 23 into a space between two rotating rollers 24,25 of different diameters. The smaller roller 24 serves as an applicatorroller while the larger roller 25 serves as a coating roller. Asindicated, the protective coating forms a coating 26 on the largerroller 25 which is then conveyed onto the body 11 of polystyrenetraveling under the coating roller 25. In addition, a third roller 27 isdisposed below the coating roller 25 so as to form a nip therewiththrough which the traveling body 11 passes. During passage, theprotective coating is applied directly to the top surface of thetraveling body 11.

The protective coating which is applied to the traveling body 11 is madeup of a metallic-based inorganic material, such as hydrated alumina(aluminum oxide trihydrate) and may also include a wetting polymercompound, such as Airflex No. 728 (a vinyl acetate/ethylene/vinylchloride polymer latex emulsion) sold by Air Products and Chemicals,Inc. Typically, the hydrated alumina comprises in weight % of from about50% to about 80% of the emulsion while the latex comprises theremainder.

The emulsion is preferably formed on the basis of 66% by weight ofhydrated alumina and 33% of Airflex No. 728 with both components beingmixed thoroughly. This mixture is applied at the rate of from 1 to 6pounds (wet) and preferably a minimum of 3.25 pounds per sheet of awidth of 48 inches and a length of 96 inches.

Thereafter, the traveling body 11 is passed into a further dryingstation 28, for example in the form of a heat tunnel, and dried so thatthe applied emulsion forms the protective coating 12 on the body 11.

Alternatively, the first drying station 21 may be omitted so that theimpregnating solution (if applied) and the protective coating areapplied in a one-step operation prior to the foamed polystyrene body 11reaching the second drying station 28.

The traveling body 11 may then be cut by suitable cutters (not shown)into panels of suitable length, for example lengths of 120 inches.Thereafter, a plurality of such panels can be bundled into larger units,for example bundles of 48 inches by 48 inches by 96 inches, bagged andbanded for shipment.

Referring to FIG. 3, the insulation barrier 10 may be employed in aroofing system which employs a steel roof deck 30. As indicated, thesteel roof deck 30 is disposed in a horizontal plane and the insulationbarrier 10 is placed as a layer directly onto the steel roof deck 30with the encapsulating layer 12 facing the metal roof deck 30.Subsequently, the barrier 10 is covered over by a barrier sheet 31 ofknown construction and an overlying membrane 32 of known construction.In this embodiment, the insulation barrier 10 may be adhered ormechanically attached to the steel roof deck 30 as a single ply system.Alternatively, multiple layers of the insulation barrier 10 may be used.

Referring to FIG. 4, wherein like reference characters indicate likeparts as above, the insulation barrier 10 may be incorporated in aballasted roof system. As indicated, the insulation barrier 10 issecured directly to the steel roof deck 30 and a membrane 33 is appliedover the insulation barrier 10. In addition, a layer of ballast 34 isapplied over the membrane 33.

Referring to FIG. 5, wherein like reference characters indicate likeparts as above, the insulation barrier 10 may be employed in a built uproof (BUR) system. In the illustrated embodiment, the insulation barrier10 is provide with a tapered top surface rather than a horizontalsurface as in the other illustrated embodiments. In addition, a rigidoverlayment 35 of known construction is applied over the insulationbarrier 10 and a BUR layer 36 is applied over the rigid overlayment 35as is known. Typically, the tapered embodiment would be tapered toaccommodate a 1/8 inch per foot slope.

Typically, the insulation barrier 10 can be installed in panels of athickness of from 1/2 inch to 10 inches or more.

The use of the fire resistant composition, such as sodium silicate, in awater solution serves to enhance the introduction of the compositioninto the interstices within the foamed polystyrene body 11. Further, theuse of the wetting agent serves as a control to allow the composition toenter and migrate into the foamed polystyrene body 11.

Referring to FIG. 6, the reaction that takes place within thepolystyrene body 11 between the fire resistant composition 37, whenused, and the metallic-based inorganic material 38, such as aluminumoxide trihydrate, is believed to be based upon a nanostructured(nanophase) material. That is, the combination, in particular, of sodiumsilicate and aluminum oxide tyrihydrate provides interfaces whichinfluence the mechanical properties of the body 11. Multilayeredsandwich-like materials are made inside the body 11 and about the cells39 thereof which may be characterized as frequent, periodic interlayerboundaries. These layers of varying composition interface to initiatecrystal structure which renders the overall product stronger.

The aluminum oxide trihydrate included within the top coating 26 isforced and continuously migrates into the penetrated area of thepolystyrene body 11 including the interstices of the body to interminglewith the sodium silicate (silica) to create a high crystalline bond.

The nanocomposite chains which are formed by the delayed polymerizationreaction taking place between the silicate and aluminum/latex emulsionproduces a strong insulation barrier product.

The insulation barrier may be used not only in roof deck systems butalso in the form of other products, such as ceiling tiles, patioenclosures and the like.

The invention thus provides a foamed polystyrene body having enhancedfire resistant characteristics and strength. Further, the inventionprovides a foamed polystyrene body which can be used as an insulationbarrier, for example in a roof installation system without need for athermal barrier.

Having now fully described the invention, it will be apparent to one ofordinary skill in the art that many changes and modifications can bemade thereto without departing from the spirit or scope of the inventionas set forth herein.

What is claimed is:
 1. A method of making a silicate-free insulationbarrier comprising the steps of:a. obtaining a body of silicate-freefoamed polystyrene having at least an upper surface; b. applying anemulsion including a metallic-based inorganic material to said uppersurface of said body; and c. drying the applied emulsion to form aprotective coating on said body.
 2. A method as set forth in claim 1wherein said emulsion comprises aluminum oxide trihydrate and latex. 3.A method as set forth in claim 1, wherein said metallic-based inorganicmaterial is selected from the group consisting of aluminum oxidetrihydrate, hydrated boron oxide, antimony oxide, titanium dioxide,magnesium hydroxide and mixtures of at least two of said materials.
 4. Amethod as set forth in claim 3, wherein said emulsion is an organicemulsion.
 5. A method as set forth in claim 4, wherein said organicemulsion is comprised of vinyl acetate, ethylene and vinyl chloridepolymer.
 6. A method as set forth in claim 1, wherein said foamedpolystyrene is selected from the group consisting of expanded andextruded polystyrene.
 7. A method of making a silicate-free insulationbarrier comprising the steps of:a. obtaining a body of foamedpolystyrene having at least an upper surface wherein said body is notimpregnated with a silicate; b. applying an emulsion including ametallic-based inorganic material to said upper surface of said body;and c. drying the applied emulsion to form a protective coating on saidbody.
 8. A method as set forth in claim 7 wherein said emulsioncomprises aluminum oxide trihydrate and latex.
 9. A method as set forthin claim 7, wherein said metallic-based inorganic material is selectedfrom the group consisting of aluminum oxide trihydrate, hydrated boronoxide, antimony oxide, titanium dioxide, magnesium hydroxide andmixtures of at least two of said materials.
 10. A method as set forth inclaim 9, wherein said emulsion is an organic emulsion.
 11. A method asset forth in claim 10, wherein said organic emulsion is comprised ofvinyl acetate, ethylene and vinyl chloride polymer.
 12. A method as setforth in claim 7, wherein said foamed polystyrene is selected from thegroup consisting of expanded and extruded polystyrene.